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#122167 - 10/01/05 09:45 PM Knock-Out Seals
Webmaster Offline


Registered: 10/07/00
Posts: 3142
Loc: NY, USA
The gutter shown in this pic contains the main feed to a number of panels at a shopping center. Some extra holes were filled with.....some interesting 'plugs.' Anyone know what they were really intended to be used for?

- renosteinke

[This message has been edited by Webmaster (edited 10-02-2005).]

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#122168 - 10/01/05 10:26 PM Re: Knock-Out Seals
mxslick Offline

Registered: 10/24/04
Posts: 785
Loc: Atomic City, ID USA
They look like the plugs plumbers use to seal lines for pressure/standing water testing.....

Someone got creative....
Stupid should be painful.

#122169 - 10/02/05 08:41 AM Re: Knock-Out Seals
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
What an electrician that did not have any 4" square blanks?

Anyway I will go with slicks thought or maybe plugs to be used when heating PVC for bending?
Bob Badger
Construction & Maintenance Electrician

#122170 - 10/02/05 08:43 AM Re: Knock-Out Seals
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
By the way I would also say they where punched out for either pulling or feeding the wires in the opposite pipes.

The folded one also.

Bob Badger
Construction & Maintenance Electrician

#122171 - 10/02/05 03:39 PM Re: Knock-Out Seals
tkb Offline

Registered: 12/04/04
Posts: 94
Loc: Massachusetts
These are T&B Push-Penny® Plugs.
I thought they were for plugging conduits. I never saw them used as KO blanks.

Plug, Conduit, Connectors (Push Penny® Plugs)

Economically seal out grout and plaster from
any fitting or raceway conforming to CSA
dimensional tolerances. Made of flexible plastic,
they push into place and are held fast by
pressure against internal surface of fitting or
raceway. Eliminates need for separate capped
bushing or steel penny and bushing.


[*] To plug open end of conduit or connector
in order to prevent ingress of
trash, dirt or moisture during construction
and remodeling.


[*] Wide range of application; can be
used with rigid metal conduit, intermediate
metal conduit, electrical
metallic tubing, all connnectors and
all bushings.

[*] Designed to stand up to normal
handling and is functionally unaffected
by moisture.

Standard Material

Standard Finish
As molded

Listed/Certified by:
CSA (LR2884, LR4484)

Conforms to:
U.L. 514B
CSA C22.2 No. 18
NFPA 70-1999 (ANSI)

Push-Penny® Plugs

Cat# Size
1470 1/2"
1471 3/4"
1472 1"
1473 1-1/4"
1474 1-1/2"
1475 2"
1476* 2-1/2"
1477* 3"
1478* 3-1/2"
1479* 4"
* Not CSA Certified
CSA File No. 2884
UL not applicable

[This message has been edited by tkb (edited 10-02-2005).]

#122172 - 10/03/05 08:43 AM Re: Knock-Out Seals
sandsnow Offline

Registered: 09/21/04
Posts: 163
Loc: Irvine, CA, USA
I wonder how many younger electricians would know what a "penny" is when used in electrical context?
Larry LeVoir
City of Irvine, CA

#122173 - 10/03/05 12:46 PM Re: Knock-Out Seals
jfwayer Offline

Registered: 05/15/05
Posts: 30
Loc: Fairmont, WV, USA
it's easy, a penny is a high current fuse link that is usually protected by the wiring in case of a fault

#122174 - 10/03/05 04:54 PM Re: Knock-Out Seals
electure Offline


Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA
"The penny" has been replaced by "The ductape" in the minds of younger guys I think, Larry.


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